For those who don’t share my fascination with diving, a saturation dive is conducted at deep depths for extended periods of time at depths of hundreds of feet. I have read with bemusement the various “deep dives” that have been conducted by various publications into the workings of modern automatic transmissions. These deep dives tend to be more akin to splashing about in the shallow end of a pool. The name Saturation Dive is an engineer’s attempt at humor, namely to convey that this series of articles is much deeper than the stereotypical deep dives. This time around, we will be taking a detailed look at the ZF 8 speed RWD transmissions.

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The ZF 8 speed transmission family has been around for a while, so a lot more information tends to be available for it than for the 9 speed. First, a quick rehash of the basics of gears that were discussed in the last saturation dive, for details please refer to the article on the ZF 9 speed. The simplest gear set consists of 2 parallel gears mounted on 2 parallel shafts. Shown in Fig. Is a gear set with a 20 tooth drive gear on the right and a 30 tooth driven gear on the left. For this gear set the speed of the driven gear is 1.5 times lower than the drive gear, and assuming no frictional losses anywhere, the torque on the driven gear is 1.5 times higher.

This gear set has a ratio of 1.5:1. This type of a gear set is usually not favorable for packaging since it requires 2 parallel shafts, and there are large separating forces that push the 2 gears apart which means that the bearings supporting the shafts have significant radial loads on them, in addition to an axial load if the gears are helical. A simple planetary arrangement is shown in Fig.. A simple planetary gear set has 3 members mounted on concentric shafts, the innermost gear is called a sun gear, the outermost gear is called the ring gear, and there are evenly spaced planetary pinions that mesh with both the sun gear and the ring gear. These pinions are free to spin around their own axes, and ride on the planetary carrier, which is the third concentric member. The radial forces in a planetary gear arrangement cancel out due to symmetry, and therefore the bearings supporting these shafts do not see much, if any radial loads. Free Arizona Drivers License Checks.